随着人类天文观测和深空探测技术的发展,传统的单天线射电望远镜的观测能力已经不能完全满足科学需要,VLBI(Very Long Baseline Interferometry)技术随着连线射电干涉仪的发展而诞生。VLBI观测利用相距几千甚至上万公里的射电望远镜同时观测同一目标源,可以将几台小口径射电望远镜等效为一个口径达到几千公里的大望远镜,因此可以大大提高观测的角分辨率。观测结束后需要将各个望远镜的观测数据通过硬盘寄送或者网络传输的方式送到VLBI数据中心进行相关处理,因此相关处理机的处理效果就关系到整次观测的成败。DiFX是一种FX型软件相关处理机,具有灵活、移植性高、数据吞吐量大、计算速率高等特点,是运行在分布式计算机平台和共享存储单元的计算机集群环境下的最成功的软件相关处理机之一。本文采用DiFX软件相关处理机,对申请到的一次CVN脉冲星观测进行了数据相关处理,并使用了DiFX特有的Pulsar Binning模式,对脉冲星的脉冲信号添加脉冲门,以增强其信噪比。并在完成后续的数据校准工作后得到了脉冲星的高分辨率图像和位置信息。对比前人工作表明,文中得出的结果较为可靠,而且在Pulsar Binning模式下信噪比明显提高。
其他摘要
As the single antenna radio telescopes haven’t satisfy the science requirements with the development of astronomical observation and deep space exploration technology, the VLBI technique emerged from radio interferometer. VLBI can improve the angular resolution because it can equivalent several small radio telescopes to one huge telescope with diameter of thousands of kilometers. After each observation the data of every station must be send to VLBI center for correlative processing, so the correlator is the most important part in the whole system. DiFX is a kind of FX style software correlator which has many advantages, such as flexible, portable, large capacity, high speed computing and so on. It is one of the most successful software correlator which is running under the distributed computer platform and large computer clusters environment. In this paper I used the DiFX to process the data from one time of CVN observation. The SNR of result has being increased by using the Pulsar Binning mode in DiFX,and I got the high resolution images and accurate positions of pulsars. Compared with previous works from other people, my results are much reliable, and the SNR has being increased obviously.
修改评论